JP2000308820A - W / O emulsion composition and method for producing the same - Google Patents

Abstract

[PROBLEMS] To provide good emulsion stability in a wide range of W / O ratios,
Provided is a W / O emulsion composition having high safety and no irritation to the skin. A W / O emulsion composition containing the following component (a) in an oil phase and the following component (b) in an aqueous phase. (A) Component: a lipophilic surfactant which is an ester of a fatty acid having 16 to 22 carbon atoms containing 60% by weight or more of unsaturated fatty acid and a polyhydric alcohol. (B) Component: a hydrophilic surfactant having an HLB of 7 or more, which is an ester of a fatty acid and a polyhydric alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water-in-oil type (hereinafter referred to as W
In particular, the present invention relates to a W / O emulsion composition suitable for use in external preparations, creams and the like, and a method for producing the same. The composition of the present invention is used for pharmaceuticals, cosmetics, foods and the like.

[0002]

2. Description of the Related Art A W / O emulsion composition can be used as a functional emulsion composition when used in medicines and cosmetics because various water-soluble substances can be added to an internal aqueous phase. In the food field, it can also be found in margarine and low fat spreads. In particular, when applied to the skin, the W / O emulsion composition is effective in preventing moisture loss that helps maintain the softness and firmness of the skin, and is resistant to sweat and water because the external phase is oil. It has the great advantage of good durability. However, on the other hand, there are problems such as defects in usability such as oiliness and low emulsion stability.

[0003] The low emulsion stability of the W / O emulsion composition is different from the oil-in-water (O / W) emulsion composition in that the electrostatic repulsion between particles in water cannot be utilized, This may be due to the lack of an effective thickener in the phase.

[0004] Generally, a W / O emulsion composition is produced by adding a lipophilic surfactant to an oil component and adding an aqueous component. And, as examples of the lipophilic surfactant, sorbitan sesquiolate, glycerol monooleate, lanolin, cholesterol and the like are known. However, the stability of the conventional W / O emulsion composition is not sufficient when a time such as distribution of a product is added. For this reason, various attempts have been made to realize an emulsion composition having excellent stability in a wide range of W / O ratios.

For example, an aqueous solution of an amino acid or a salt thereof is mixed with a lipophilic surfactant to form a gel, and the obtained gel is dispersed in an oily component, and then an aqueous component is added thereto to form a W / O emulsion composition. Methods for obtaining objects have been reported (Y. Kumano, S. Nakamura, S. Tahara, S. Ohta: J. So
c. Cosmet. Chem, 28, 285 (1977)). However,
In this method, the surfactant used is a liquid at room temperature and has an organic-inorganic ratio (IOB) of 0.4 to 0.7.
, And itself have a lamellar structure, which makes it difficult to apply to a wide range of applications.

On the other hand, among nonionic surfactants, polyoxyethylene surfactants (emulsifiers), which are said to have a high emulsifying power, are known to emulsify and disperse an aqueous component exceeding 90% by weight ( H. Kunieda et a
l. , Colloid and Surfaces, 2
4, 225 (1987)). However, the polyoxyethylene-based surfactant accounts for 20% by weight of the oily component.
It is necessary to mix the above, moreover, the surfactant,
Since the polyoxyethylene chain is decomposed with time to form formalin, for example, when applied to creams containing a large amount of an aqueous component, the resulting emulsion composition has high irritation to the skin There are problems such as.

Further, a W / O emulsion composition having high safety and no irritation to the skin is disclosed in JP-A-9-23.
No. 9259 discloses a high water-containing W / O emulsion composition in which a specific sucrose fatty acid ester is used as an emulsifier and a large amount of an aqueous component is stably dispersed with a small amount of an emulsifier. If the dispersed aqueous phase exceeds the close packed volume fraction of 0.74 of the spheres as in such a composition, the dispersed aqueous phase becomes polygonal and the emulsified system is significantly thickened,
The frequency of collision and coalescence between the dispersed droplets is reduced, and the emulsion stability is naturally increased. On the other hand, of course, such a high water content is required as an emulsion composition having good emulsion stability in a wider range of W / O ratio.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to provide a wide range of W / O.
It is an object of the present invention to provide a W / O emulsion composition having good emulsification stability in a ratio, high safety, and no irritation to skin, and a method for producing the same.

[0009]

That is, the first aspect of the present invention is as follows.
The gist of the present invention resides in a W / O emulsion composition comprising the following component (a) in an oil phase and the following component (b) in an aqueous phase. (A) Component: a lipophilic surfactant which is an ester of a fatty acid having 16 to 22 carbon atoms containing 60% by weight or more of unsaturated fatty acid and a polyhydric alcohol. (B) Component: a hydrophilic surfactant having an HLB of 7 or more, which is an ester of a fatty acid and a polyhydric alcohol.

A second gist of the present invention is to provide a W / O type wherein the oil component in which the component (a) is dissolved and the aqueous component in which the component (b) is dissolved are mixed. The present invention relates to a method for producing an emulsion composition.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

(Oily Component) The oil component used in the oil phase can be selected from a wide range, and is not particularly limited.
As the oily component, for example, hydrocarbons, esters, waxes, waxes, silicone oils, and one or a mixture of two or more thereof can be applied.

Specific examples of the oily component include hydrocarbons such as n-heptane, n-octane, n-decane, cyclohexane, hexadecane, liquid paraffin, petrolatum, squalene, squalane, ethers such as diheptyl ether, and ethylene. Diethers such as glycol dibutyl ether, long-chain amino alcohols such as sphingosine,
Examples include long-chain aldehydes, long-chain ketones, terpenoids, steroids, carotenoids, waxes, acylglycerols, ether glycerides, ceramides, phospholipids, glycolipids, phosphoglycolipids, sulfate lipids, amino acid lipids, and the like. In addition, a mixture of animal oils such as fish oil, vegetable oils such as soybean oil, and mineral oils may be used, and the melting point and solid fat content of the oils and fats are not particularly limited. Further, silicone oils such as dimethyl silicon, cyclic silicon, methylphenyl silicon, and polyether-modified silicon can also be used.

(Lipophilic Surfactant) The lipophilic surfactant contained as the component (a) in the oil phase is a fatty acid having 16 to 22 carbon atoms containing 60% by weight or more of unsaturated fatty acid and a polyhydric alcohol. Is an ester of Examples of the above-mentioned unsaturated fatty acids which become the hydrophobic part of the lipophilic surfactant include palmitooleic acid, oleic acid, and erucic acid. Among them, erucic acid is preferable. Examples of the polyhydric alcohol serving as a hydrophilic portion of the lipophilic surfactant include sucrose, lactose,
Glucose, polyglycerin, sorbitol and sorbitan are mentioned, and among them, one or more polyhydric alcohols selected from the group consisting of sucrose, polyglycerin, sorbitol and sorbitan are preferred.

More specifically, the sucrose fatty acid ester has an HLB of 3 or less, and the polyglycerin fatty acid ester has a polymerization degree of polyglycerin of 4 to 4.
20, and the saponification value of polyglycerin fatty acid ester (based on the standard method for analyzing fats and oils, edited by Japan Oil Chemists' Association)
Is preferably 90 to 150 (particularly 100 to 140), and in the sorbitan fatty acid ester, the degree of substitution is preferably 1 to 3. These lipophilic surfactants are easily used in the emulsion composition of the present invention because they are easily soluble in oily components and the resulting emulsion composition has excellent stability.

HLB is an atlas formula: HLB = 20 ×
Value calculated by (1-saponification value / neutralization value) (Koshobo
Toru Hidaka, "Emulsifiers for foods, 2nd edition", etc., and the saponification value and neutralization value can be determined by general methods of oil and fat analysis, respectively. ).

An example of the most preferred lipophilic surfactant is sucrose erucate or sucrose oleate, an ester of HLB 3 or less, hexaglycerin erucate or decaglycerin erucate, Esters having a saponification value of 90 to 150, sorbitan sesquiolate, and sorbitan monooleate are exemplified.

The lipophilic surfactant is contained in the oil phase in an amount of usually 0.1 to 30% by weight, preferably 1 to 10% by weight, based on the total amount of the oily component and the lipophilic surfactant. . Two or more lipophilic surfactants may be used in combination, respectively. In this case, the combination of the two can be appropriately selected.

(Hydrophilic Surfactant) The hydrophilic surfactant contained as the component (b) in the aqueous phase is an ester of a fatty acid and a polyhydric alcohol having an HLB of 7 or more. The constituent fatty acids preferably have 10 to 24 carbon atoms. Also,
The constituent fatty acids are not limited to linear, branched, saturated, or unsaturated conditions. On the other hand, polyhydric alcohols include sucrose and / or
Alternatively, polyglycerin is preferred. Generally, HLB5 is the lower limit of the hydrophilic surfactant, but in the present invention, the above ester having HLB of 7 or more, preferably HLB of 11 or more is used.

The polyglycerin fatty acid ester includes
Polyglycerin fatty acid esters having a cloud point of 50 ° C. or higher as measured in a 5% by weight saline solution are preferred. The cloud point is a well-known property value of a polyoxyethylene-based surfactant. Polyglycerin fatty acid esters generally have a higher cloud point and higher than the boiling point of water, as compared with polyoxyethylene-based surfactants. Such cloudy weather
It can be easily measured by using an appropriate salt aqueous solution (see JP-A-9-157386). Usually, the stronger the hydrophilicity, the higher the cloud point. At the same esterification rate, an ester composition having a higher monoester content has higher hydrophilicity and a higher cloud point.

In the present invention, the cloud point of the polyglycerin fatty acid ester is a value measured in a 5% by weight saline solution. That is, for an aqueous solution in which 1% by weight of polyglycerin fatty acid ester is dissolved in a 5% by weight saline solution, 0%
The mixture is shaken, stirred and allowed to stand at an arbitrary temperature in the range of -100 ° C in increments of 2-5 ° C, and the state in which the polyglycerin fatty acid ester is separated into an oily or gel-like form to form a heterogeneous aqueous solution is observed. By doing so, it is measured. The temperature at which this non-uniform state is exhibited is called the cloud point.

Examples of the most preferred hydrophilic surfactant include sucrose palmitate, sucrose stearate, and decaglycerin stearate having a cloud point of 90 ° C. or more in a 5% by weight saline solution. And the like. The hydrophilic surfactant is contained in the aqueous phase,
As a ratio to the total amount of the aqueous component and the hydrophilic surfactant, it is usually 0.05 to 10% by weight, preferably 0.1 to 10% by weight.
5% by weight is contained. Two or more hydrophilic surfactants may be used in combination, and in this case, the combination of both can be appropriately selected.

When a hydrophilic surfactant having an HLB of 7 or more, which is an ester of a fatty acid and a polyhydric alcohol, is not used,
Alternatively, when a hydrophilic surfactant other than the above is used, W / O emulsification is impossible, or even if possible, the stability of the W / O emulsion composition is significantly deteriorated.

(Aqueous Component) In addition to the hydrophilic surfactant, various water-soluble substances can be added to water as the aqueous component depending on the use of the W / O emulsion composition. . In the case of pharmaceuticals / cosmetics, a polyhydric alcohol as a moisturizing / stability improving agent and various known moisturizing agents are usually added.

Examples of the polyhydric alcohol include polyhydric alcohols having 3 to 6 carbon atoms such as glycerin, propylene glycol, erythritol, xylitol and sorbitol; monosaccharides such as xylose, glucose, fructose and galactose; sucrose; Examples include disaccharides such as maltose and trehalose. Among them, glycerin, sorbitol, sucrose and lactose are preferred. These polyhydric alcohols are usually added in the range of 2 to 50% by weight based on the total amount of water and the polyhydric alcohol.

Examples of the humectant include PCA (pyrrolidone carboxylate), organic acid salts such as lactic acid, hyaluronate, water-soluble collagen, royal jelly extract, placenta extract, chondroitic acid, and the like. In addition, the aqueous component further contains, if necessary, various thickeners such as aliphatic monohydric alcohols having 1 to 3 carbon atoms, xanthan gum, carboxymethylcellulose salts, carboxyvinyl polymers, and filming agents such as polyvinyl alcohol. It can also be added.

When the composition of the present invention is used in cosmetics, the additional components include an ultraviolet absorber, a hair root activator,
Examples include antioxidants, whitening agents, astringents, nutrients, perfumes, pigments, preservatives, chelating agents, and the like. In addition, examples of the additional components used in pharmaceuticals include, in addition to the above, various medicinal components such as anti-inflammatory agents, antihistamines, blood circulation promoters, hormones, analgesics, and antipruritic agents. In addition,
In the present invention, in order to stabilize the emulsification in the oil component or the aqueous component, various thickeners, cosurfactants, and the like may be added.

(Volume Ratio of Water Phase) The ratio of the oil phase water phase in the W / O emulsion composition of the present invention is not particularly limited. The volume ratio of the aqueous phase is usually 50 to 99%, but in the present invention, an emulsion composition having a high internal aqueous phase ratio within the range of 80 to 99% is also possible.

(Method for Producing W / O Emulsion Composition) The method for producing the W / O emulsion composition of the present invention comprises dissolving the oily component obtained by dissolving the component (a) and the component (b) described above. And a mixed aqueous component. That is, the composition of the present invention is, specifically,
It can be easily prepared by adding a predetermined amount of the lipophilic surfactant of the component (a) and dropping an aqueous component in which a predetermined amount of the component (b) is dissolved with stirring into an oil component. At this time, it is preferable that the components (a) and (b) are completely dissolved in each phase. Therefore, it is preferable to perform heating and stirring as needed. Also, from the method in which a desired composition is measured and emulsified at a time, emulsification is first started by using an amount of about 70% from half of the aqueous component, and thereafter,
It is preferable to adopt a method of gradually adding an aqueous component.

The stirring can be performed with a commonly used stirrer such as a propeller mixer or a disper. Although the number of rotations cannot be determined unconditionally because it differs depending on the capacity, it is usually 2
The temperature is in the range of 0 to 10,000 rpm, and the temperature during stirring is in the range of 60 to 70 ° C. The particle size of the water droplet can be adjusted to 0.1 to 50 by adjusting the stirring intensity (= power × time).
Can be controlled between microns.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. The raw materials used in the following examples are as shown in Tables 1 and 2 below.

[0032]

[Table 1]

[0033]

[Table 2]

<Storage Test> The emulsion composition was stored under various temperature conditions of 5 ° C., room temperature and 40 ° C., and the emulsion stability at that time was visually observed and evaluated according to the following four criteria shown in Table 3. I do.

[0035]

[Table 3]

Examples 1 to 12 and Comparative Examples 1 to 6 W / O emulsion compositions having the composition (weight ratio) shown in Table 4 were prepared by using the surfactants shown in Table 5 by the following procedures. . Then, a storage test was performed, and the results are shown in Table 5.

First, a lipophilic surfactant and an oil component were uniformly dissolved to prepare an oil solution having a surfactant concentration of 10% by weight in the oil phase. On the other hand, if necessary, an aqueous component such as glycerin or sorbitol is added to ion-exchanged water, and then the hydrophilic surfactant is uniformly dissolved so that the surfactant concentration in the aqueous phase becomes 0.1% by weight. The components were prepared. Table 4 shows the details of the composition of the emulsion composition.

Next, an aqueous component was dropped into the oil solution over 5 minutes using a thermostat at a temperature of 60 to 70 ° C., a magnetic stirrer and a stirrer to obtain an internal aqueous phase emulsion composition. Confirmation that the composition was a W / O emulsion composition was made by a diffusion test of the composition into water.

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

According to the present invention, it is stable for a long time in a wide range of W / O ratio, high in safety and high in irritation to skin, which was difficult with the conventional W / O emulsion composition. An emulsion composition is provided that is free of urea. Since various water-soluble components and oil-soluble components can be added to the composition of the present invention, it can be suitably used particularly for various skin external preparations, various creams such as emollient creams and massage creams. it can. Moreover, since a creamy product can be basically obtained only with an oil component, an emulsifier, water and a water-soluble component, it is preferable from the viewpoint of skin irritation and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01F 17/34 B01F 17/34 (72) Inventor Yuko Watanabe 1-3-9 Ginza, Chuo-ku, Tokyo Mitsubishi Chemical Chemicals Co., Ltd. (72) Inventor Mikio Tsuruta 1-3-9 Ginza, Chuo-ku, Tokyo Mitsubishi Chemical Foods Co., Ltd. F-term (reference) 4B026 DG01 DG11 DH01 DK01 DK03 DK04 DX05 4C076 AA17 BB31 DD08 DD34 DD46 DD68 FF16 FF43 FF56 4C083 AA122 AC022 AC132 AC391 AC392 AC421 AC422 AC441 AC442 AD172 AD191 AD192 BB02 BB03 DD32 FF01 4D077 AA02 AA04 AA09 AB08 AB11 AB12 AC02 BA01 BA04 BA07 CA01 CA12 CA13 DC33Y DCYABY DCYY DCY AB12Y AB28Y AB33X AB38Y BA01 BA07 BB06 CA04 CA20 DA01 DA02 EA01 EA02 EA07 EA10 FA01

Claims (14)

[Claims] 1. A W / O comprising the following component (a) in an oil phase and the following component (b) in an aqueous phase:
Emulsion composition. (A) Component: a lipophilic surfactant which is an ester of a fatty acid having 16 to 22 carbon atoms containing 60% by weight or more of unsaturated fatty acid and a polyhydric alcohol. (B) Component: a hydrophilic surfactant having an HLB of 7 or more, which is an ester of a fatty acid and a polyhydric alcohol. 2. The composition according to claim 1, wherein the unsaturated fatty acid constituting component (a) is erucic acid. 3. The polyhydric alcohol constituting the component (a) is:
The composition according to claim 1 or 2, wherein the composition is at least one polyhydric alcohol selected from the group consisting of sucrose, polyglycerin, sorbitol and sorbitan. 4. The sucrose fatty acid ester of component (a) is HL
The composition according to claim 3, wherein the composition is B3 or less. 5. The composition according to claim 3, wherein the degree of polymerization of the polyglycerol constituting the polyglycerol fatty acid ester of the component (a) is from 4 to 20. 6. The composition according to claim 5, wherein the polyglycerol fatty acid ester of component (a) has a saponification value of 90 to 150. 7. The composition according to claim 3, wherein the sorbitan fatty acid ester of the component (a) has a degree of substitution of 1 to 3. 8. The component (b), wherein the constituent fatty acid has 10 to 2 carbon atoms.
The composition according to claim 1, wherein the composition is 4. 9. The polyhydric alcohol constituting the component (b) is sucrose and / or polyglycerin.
The composition according to any one of the above. 10. The composition according to claim 9, wherein the component (b) is a sucrose fatty acid ester having an HLB of 11 or more. 11. The composition according to claim 8, wherein the component (b) is a polyglycerin fatty acid ester having a cloud point (measured in a 5% by weight saline solution) of 50 ° C. or higher. 12. The composition according to claim 1, wherein the amount of the component (a) is 0.1 to 30% by weight based on the total amount of the oily component and the lipophilic surfactant. 13. The composition according to claim 1, wherein the amount of the component (b) is 0.05 to 10% by weight based on the total amount of the aqueous component and the hydrophilic surfactant. 14. A W / O emulsion characterized by mixing an oily component in which the component (a) according to claim 1 is dissolved and an aqueous component in which the component (b) according to claim 1 is dissolved. A method for producing the composition.